- Library Home /
- Search Collections /
- Open Collections /
- Browse Collections /
- UBC Theses and Dissertations /
- Predicted concentrations of polychlorinated dibenzo-p-dioxins...
Open Collections
UBC Theses and Dissertations
UBC Theses and Dissertations
Predicted concentrations of polychlorinated dibenzo-p-dioxins and furans in fat tissue due to chlorophenate exposure in B.C. sawmills Campbell, Catherine Ann
Abstract
Chlorophenols were used to prevent sapstain fungal growth on lumber in sawmills located in Canada, the United States Scandinavia, and elsewhere, from the 1940s to the late 1980s. Elevated levels of chlorophenols have been measured in the urine of sawmill workers particularly those with dermal exposure. Since polychlorinated dibenzodioxins (PCDDs) and furans (PCDFs) are contaminants created in the manufacture of chlorophenols, it is expected that sawmill workers were exposed. PCDD/Fs have half-lives on the order of years and accumulate in adipose tissue. Biological monitoring is not easily carried out due to its invasive nature and cost, consequently little information exists on PCDD/F levels in sawmill workers. In a cohort of Canadian sawmill workers assembled for a cancer incidence and mortality study, we estimated the adipose tissue concentrations of PCDD/F compounds, using a singlecompartment pharmacokinetic model. Estimates of dermal and inhalation exposure to chlorophenols throughout the working lives of the sawmill workers were combined with PCDD/F contamination levels, half-lives, and absorption efficiencies to estimate tissue concentrations. Each variable in the model was assigned a distribution based on literaturereported data, as well as information about the sawmill cohort. The predicted distributions of PCDD/F concentrations were then estimated using 5,000-run Monte Carlo analyses. Predicted median adipose tissue concentrations of all dioxins and tetra- and penta-chlorinated furans among the sawmill workers were similar to background levels in unexposed residents of the same region, though about 10 to 30% of sawmill workers were estimated to have elevated levels of these congeners. Median levels of hexa-, hepta-, and octa-chlorinated furans were predicted to be 2 to 15 times background levels. Sensitivity analyses indicate that the variability of the model predictions was most influenced by estimates of PCDD/F skin absorption efficiency, duration of employment at the sawmill, and levels of PCDD/F in chlorophenols.
Item Metadata
Title |
Predicted concentrations of polychlorinated dibenzo-p-dioxins and furans in fat tissue due to chlorophenate exposure in B.C. sawmills
|
Creator | |
Publisher |
University of British Columbia
|
Date Issued |
1995
|
Description |
Chlorophenols were used to prevent sapstain fungal growth on lumber in sawmills located in
Canada, the United States Scandinavia, and elsewhere, from the 1940s to the late 1980s.
Elevated levels of chlorophenols have been measured in the urine of sawmill workers
particularly those with dermal exposure. Since polychlorinated dibenzodioxins (PCDDs) and
furans (PCDFs) are contaminants created in the manufacture of chlorophenols, it is expected
that sawmill workers were exposed. PCDD/Fs have half-lives on the order of years and
accumulate in adipose tissue. Biological monitoring is not easily carried out due to its
invasive nature and cost, consequently little information exists on PCDD/F levels in sawmill
workers.
In a cohort of Canadian sawmill workers assembled for a cancer incidence and mortality
study, we estimated the adipose tissue concentrations of PCDD/F compounds, using a singlecompartment
pharmacokinetic model. Estimates of dermal and inhalation exposure to
chlorophenols throughout the working lives of the sawmill workers were combined with
PCDD/F contamination levels, half-lives, and absorption efficiencies to estimate tissue
concentrations. Each variable in the model was assigned a distribution based on literaturereported
data, as well as information about the sawmill cohort. The predicted distributions of
PCDD/F concentrations were then estimated using 5,000-run Monte Carlo analyses. Predicted
median adipose tissue concentrations of all dioxins and tetra- and penta-chlorinated furans
among the sawmill workers were similar to background levels in unexposed residents of the
same region, though about 10 to 30% of sawmill workers were estimated to have elevated
levels of these congeners. Median levels of hexa-, hepta-, and octa-chlorinated furans were
predicted to be 2 to 15 times background levels. Sensitivity analyses indicate that the variability of the model predictions was most influenced by estimates of PCDD/F skin
absorption efficiency, duration of employment at the sawmill, and levels of PCDD/F in
chlorophenols.
|
Extent |
7998680 bytes
|
Genre | |
Type | |
File Format |
application/pdf
|
Language |
eng
|
Date Available |
2009-02-03
|
Provider |
Vancouver : University of British Columbia Library
|
Rights |
For non-commercial purposes only, such as research, private study and education. Additional conditions apply, see Terms of Use https://open.library.ubc.ca/terms_of_use.
|
DOI |
10.14288/1.0086970
|
URI | |
Degree | |
Program | |
Affiliation | |
Degree Grantor |
University of British Columbia
|
Graduation Date |
1996-05
|
Campus | |
Scholarly Level |
Graduate
|
Aggregated Source Repository |
DSpace
|
Item Media
Item Citations and Data
Rights
For non-commercial purposes only, such as research, private study and education. Additional conditions apply, see Terms of Use https://open.library.ubc.ca/terms_of_use.